Bison level polywoven dunnage air bags are designed for light-duty bracing and cushioning in truck shipments. They are a convenient and cost-effective solution for filling the void space between pallet loads or boxes. Bison polywoven bags are composed of an air-tight polyethylene inner layer with a reusable valve and a strong, elastic polypropylene outer layer. The bags are flexible, which allows you to fill up every shape and random space without damaging the product.